/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.feilong.lib.net.ftp.parser;

import java.text.ParseException;
import java.util.Calendar;

import com.feilong.lib.net.ftp.Configurable;
import com.feilong.lib.net.ftp.FTPClientConfig;

/**
 * <p>
 * This abstract class implements the common timestamp parsing
 * algorithm for all the concrete parsers. Classes derived from
 * this one will parse file listings via a supplied regular expression
 * that pulls out the date portion as a separate string which is
 * passed to the underlying {@link FTPTimestampParser delegate} to
 * handle parsing of the file timestamp.
 * <p>
 * This class also implements the {@link Configurable Configurable}
 * interface to allow the parser to be configured from the outside.
 *
 * @since 1.4
 */
public abstract class ConfigurableFTPFileEntryParserImpl extends RegexFTPFileEntryParserImpl implements Configurable{

    private final FTPTimestampParser timestampParser;

    /**
     * constructor for this abstract class.
     * 
     * @param regex
     *            Regular expression used main parsing of the
     *            file listing.
     */
    public ConfigurableFTPFileEntryParserImpl(String regex){
        super(regex);
        this.timestampParser = new FTPTimestampParserImpl();
    }

    /**
     * constructor for this abstract class.
     * 
     * @param regex
     *            Regular expression used main parsing of the
     *            file listing.
     * @param flags
     *            the flags to apply, see
     *            {@link java.util.regex.Pattern#compile(String, int) Pattern#compile(String, int)}. Use 0 for none.
     * @since 3.4
     */
    public ConfigurableFTPFileEntryParserImpl(String regex, int flags){
        super(regex, flags);
        this.timestampParser = new FTPTimestampParserImpl();
    }

    /**
     * This method is called by the concrete parsers to delegate
     * timestamp parsing to the timestamp parser.
     *
     * @param timestampStr
     *            the timestamp string pulled from the
     *            file listing by the regular expression parser, to be submitted
     *            to the <code>timestampParser</code> for extracting the timestamp.
     * @return a <code>java.util.Calendar</code> containing results of the
     *         timestamp parse.
     * @throws ParseException
     *             on parse error
     */
    public Calendar parseTimestamp(String timestampStr) throws ParseException{
        return this.timestampParser.parseTimestamp(timestampStr);
    }

    /**
     * Implementation of the {@link Configurable Configurable}
     * interface. Configures this parser by delegating to the
     * underlying Configurable FTPTimestampParser implementation, '
     * passing it the supplied {@link FTPClientConfig FTPClientConfig}
     * if that is non-null or a default configuration defined by
     * each concrete subclass.
     *
     * @param config
     *            the configuration to be used to configure this parser.
     *            If it is null, a default configuration defined by
     *            each concrete subclass is used instead.
     */
    @Override
    public void configure(FTPClientConfig config){
        if (this.timestampParser instanceof Configurable){
            FTPClientConfig defaultCfg = getDefaultConfiguration();
            if (config != null){
                if (null == config.getDefaultDateFormatStr()){
                    config.setDefaultDateFormatStr(defaultCfg.getDefaultDateFormatStr());
                }
                if (null == config.getRecentDateFormatStr()){
                    config.setRecentDateFormatStr(defaultCfg.getRecentDateFormatStr());
                }
                ((Configurable) this.timestampParser).configure(config);
            }else{
                ((Configurable) this.timestampParser).configure(defaultCfg);
            }
        }
    }

    /**
     * Each concrete subclass must define this member to create
     * a default configuration to be used when that subclass is
     * instantiated without a {@link FTPClientConfig FTPClientConfig}
     * parameter being specified.
     * 
     * @return the default configuration for the subclass.
     */
    protected abstract FTPClientConfig getDefaultConfiguration();
}
